Hydrogenation of carbon monoxide to normally solid, high molecular weight, hydrocarbon polymers with reduced metal phosphomolybdate catalysts



United States Herrick R. Arnold and Frank S. Fawcett, Wilmington,

Del., and Benjamin W. Howls, West Chester, Pa., assignors to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application July 16, 1953 Serial No. 368,488

14 Claims. (Cl. 260-2) This invention relates to the preparation of high molecular weight essentially hydrocarbon products. More particularly, this invention relates to a novel catalytic process for preparing normally solid, high molecular weight, hydrocarbons from carbon monoxide and hydrogen.

It is known that in the presence of certain catalysts and under Well defined conditions of temperature and pressure, carbon monoxide and hydrogen react to form methanol and branched chain higher alcohols. It is also known that under other conditions the reaction between carbon monoxide and hydrogen can be directed to produce hydrocarbons as the principal products of the reaction. Cobalt-containing, ruthenium-containing, and iron-containing catalysts are particularly well known for this reaction. The hydrocarbons obtained with these catalysts,

however, are of relatively low molecular weight. There-.

fore, it the hydrogenation is to be carried out to produce high molecular weight hydrocarbon products, new processes employing more etfective catalysts are required.

It is an object of this invention to provide a novel process for the preparation of high molecular Weight essentially hydrocarbon products. A further object is to provide a novel catalytic process for preparing normally solid, high molecular weight, hydrocarbons from carbon monoxide and hydrogen. Other objects will appear hereinafter.

These and other objects of this invention are accomplished by the following process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 125 to 350 C. under a pressure of at least 200 atmospheres and in contact with a reduced metal phosphomolybdate which is the product obtained by reducing in hydrogen at atmospheric pressure and at a temperature in excess of 375 C. for at least six hours a phosphomolybdic acid salt of a metal of groups I-A, IB, II-B, III-B, VII-A and the base metals of group VIII of the periodic table. It has now been found that if instead of using the previously known iron, cobalt-, and ruthenium-containing catalysts, there is used a metal phosphomolybdate catalyst as herein specified which has been prereduced in accord with the procedure described in the concurrently filed U. S. patent application of Arnold and Howk, Serial No. 368,489, now U. S. Patent 2,788,258, issued April 9, 1957, the principal prodnets of the reaction are high molecular weight hydrocarbons.

In producing the normally solid, high molecular weight, hydrocarbons in accord with this invention, a pressure reactor is charged with a liquid diluent and the reduced metal phosphomolybdate catalyst, the reactor is swept with oxygen-free nitrogen, cooled to C., and evacuated. The reactor is then pressured to a specific level with a carbon monoxide/hydrogen gas mixture of predetermined composition and the reaction mixture is heated to aren't ice between 125 and 350 C. until the desired degree of reaction has taken place. Throughout the reaction period the pressure within the reactor is maintained at the desired level by re-pressuring with a carbon monoxide/hydrogen gas mixture of the same or of different composition from that initially used. After reaction is complete, the reactor is permitted to cool, opened, the contents discharged, and filtered. The solid polymeric product is separated from the catalyst by extraction or by other means known to those skilled in the art.

The examples which follow are submitted to illustrate and not to limit this invention. Unless otherwise stated, the reactor employed is of approximately 400 cc. capacity, inherent viscosity refers to measurements made at 0.1% concentration in tetrahydronaphthalene at 125 C., and the gas composition is a 2:1 molar hydrogen-carbon monoxide mixture.

Example 1 A mixture of 100 cc. of xylene and 10 g. of reduced nickel phosphomolybdate in powder form, prepared as described subsequently, is heated at 250 C. with a hydrogen-carbon monoxide gas mixture under 1000 atmospheres total gas pressure. During 15 hours the gas absorption amounts to 735 atmospheres. Extraction of the crude solid product with refluxing benzene, followed by dilution of the extract with methanol, yields 0.33 g. of solid precipitate. Similar extraction with xylene and precipitation yields 1.00 g. of a white hydrocarbon polymer having inherent viscosity 0.97.

The above experiment is repeated at 225 C. using a reduced nickel phosphomolybdate in the form of 8-14 mesh pellets. Under these conditions a gas absorption corresponding to 955 atmospheres is observed and there is obtained 3.47 g. of a xylene-soluble polymer having an inherent viscosity of 1.68.

The reduced nickel phosphomolybdate is prepared as follows:

A nickel salt of phospho-ll-molybdic acid having the composition Ni H [P (Mo O ]-24H O or ZNiO P 0 22M-oO 28H;,O is prepared by dissolving 100 g. of phospho-ll-molybdic acid and 43.6 g. of nickel nitrate hexahydrate in one liter of distilled water and concentrating the solution on a steam bath until incipient crystallization of the nickel salt occurs. The solution is then slowly cooled to room temperature, whereupon the nickel salt is crystallized. The crystals are isolated by filtration and dried in vacuo over phosphorus pentoxide.

Sixty-five grams (50 cc.) of the yellow crystalline nickel phospho-ll-molybdate is placed in a heat-resistant glass tube mounted in an electric furnace, and hydrogen at the rate of 50 liters/ hour, equivalent to a space velocity of 1000 reciprocal hours, is passed through the tube at essentially atmospheric pressure. The system is then heated up from room temperature to 400 C. at the rate of about -95 C./hr. and held under these conditions for 16.75 hours. During the heating up period in the temperature range -200 C. the water of crystallization is driven off, the nickel phosphomolybdate undergoing a simultaneous color change from yellow to orange. In the interval 200-300" C. no further water is formed and no significant change in appearance of the nickel phosphomolybdate occurs. At approximately 300 C. reduction is initiated, as indicated by the evolution of water, and a gradual change in color of the nickel salt occurs from orange to black. At 400 C. reduction proceeds more rapidly, however, and is continued at this temperature for a period of 16.75 hours. The reduced product is then cooled to room temperature in hydrogen, flushed at room temperature with nitrogen and discharged. and sealed under nitrogen.

The-reducedmickel phosphomolybdate is black and highly pyrophoric and has to be handledat all times-in an inert atmosphere in order to avoid oxidation. Its X-ray diffraetion pattern shows that it is essentially amorphous and its empirical formula, as indicated "by elementary analysis, is Ni -P (Mo G5) ,--as compared to 'ZNiO "P 0 "22MoO *28 H O *for 'the unreduced nickel salt.

Example "11 he procedu in h fi tpa n Examp s-mpea w t a redu e p deredt ob tp osnhqmq yhdat catal s eprep eda se ib d abse uemly- Unde ese conditions the total pressure dr op corresppnd s $031,051;- mosphe e Ihe eis htai e let-o be zene'sqh b ma eria and 4.12 a o ny eneeo ubl po y r :thela t ha insinheren scasity 9 ans M- LB--'1..2:3:1:3Q.51.C-

Example -11] Ihe-p Pc du e-i .th -Ai how o taxnnleliist epe n with g. of a reduced powdered iron phosphom qlybdate catalyst, prepared as described subsequently. After 9.5 hours at 240 C there is obtained 0.l 8.g. of benzenesoluble'product and 1:68 g. of xylene-soluble polymer,the latter 'havingaan inherehtwiscosity .of 2.23 "and M. P. 130-13215" C.

Example '-IV Examle V T eo oc dure n theyfirstp o E m el isrenea e with 10 g. ofaredueedpowdered zincphosphomolybdate catalyst, preparedasdescribed subsequently. Under these conditions the gas absorption amounts to 975 atmos pheres. There obtained 0.87 .g. .of ;benzene.soluble product ;and;2.09 g. .;of zylene soluble polymer-..having an inherent .w'scosity 1.42 .and :P. 129-131 C.

Example VI A .o 1.0. a m ess and like :o fi L ZS1 d alum num .ph snhomplr slate -:.cat 1 y t,-r repared :as described subsequently, is heated at 225 ;Q. under 13. pressure UQ .a flrnsr 1 er .o ally r g nzearbpn; mon xide n... dtgas- Du in v eh ursthe :ea absomti n nt to A, w, 0 atmospheres. .Ihereisrobtaint d. 0.-5,0;g. of xylene soluble polymer having inherent -viscosity 2.44 and ;M. ;-P. 129- 132.C.

ExampleaVll A mixture of 5100 cc. "of xylene and 10g. .of ,a reduced silver-phosphomolybdate catalyst,.pr epared as described subsequently, is heatedat 225 .C. and pressured to @1000 atmospheres with a hydrogen-carbon monoxide mixed gas-mixture. During a period of',15 hours, a 420 atmospheres gas absorption oceurs,and there obtained 1.57

g. ofnxylene solu ble'hydrocarbon polymer.

Example VIII A mix u o 0 c o avlcne ,an jzfltle- Q Z Il d po dered. pota um ph sp molr dateca ly nnrenared a v. estr bie subsequently, fi heateda 121. 6' prev ureo 11999. a m pheres w he' .nlrosene atbqnmqn- Metal Phosphomolybdates Reduced Metal Phos- The products obtainedwbyzreduction of the metal phosphomolybdates are all gray 510 black pyrophoric solids having. surface areas .in'ztheirangenf 4010 .130 mB/gtas determined by the :procedure described in .a paper by P. Emmett, entitled As-new method for measuring the surface.areasnfifinelydividedmaterials and for determin ing the size. of .particles,. Am.., Soc. for-Testing .Materials, March .4, 194:1,Symp0sium on NewTMethods for'Particle Size Determination in theSub-sieve SRange. Their X-ray difiractiompatterns'indicate that-they are principallyamoo phous, like reduced1nickel.phosphomolybdate.

"Thetexamples have illustrated certain conditions of temperature, pressure, catalyst concentration, carbon monoxidelhydrogemmixed gascomposition, etc. It is to be understood that these are interdependent variables and that modification -i-none-setof conditions may-.trequire compensating 'adiustmentsin the others.

' The process =of-this invention can be operated as a batch,as'a semi-continuous, or as a continuous -up-floW, down-flow,-orz-counter currentoperation. It can also'be operated -as -=a-co-current flow or boiling =bed operation.

"The mole --ratioof carbon-monoxide to hydrogen in the gas mixture -'-may vary-from -10:-1 to 1:5. Usually, mole ratios of from 3 ;1 to 1:2 are used because gas mixtures/in this rangeof composition are ordinarily available in' large scale and give --optimum results --from the standpoint' of yield of desired high molecular "weight hydrocarbons.

Thetemperature =at-which thehydrogenation of--the carbon monoxide is-efiected*lies' in the range 0f'1 2 5 ,to 350 C. Because "good reaction rates, with 'best yields of desired high molecular weight hydrocarbons, are obtained in the range 1-50"to *2'75' .C., this range embraces the preferred operating "lIBlItlPEIflflll'fi --conditions.

The process "is usually operated under a total pressure of at least 200 atmospheres. tBecause "better yields of desired-high molecular e h hyd ca bon wi h a murnutilizatiomof the carbon monoxide and' hy drogen, a e aqh e b .us n nres u e .in exces o 400; t im he es, th 12 1: of uc pr ssu es i eco eafica and emr qe a p efe red mod .ope at nhe m imum p essur w ich is n i zab e i dic ated. ,s npl t e hanica l m ta ion of t e equipme us diB r-pra tical reasons, pressures above'5000 atmospheres are genall nq used and th therefor const t es .a pra tic gpne nr ss re imitxide asmi u Ihegasabso pti ni n inga4 -hou a;

cact ongpen d amounts' t0..97,0.atmosph res- 'Ihmcwide product "is separated into a solid portion ,anjdtwoflli qnid anol, decahydronaphthalene, tetrahydronaphthalene, benzene, toluene, xylene, cyclohexanone, methyl isobutyl ketone, and the like. The reaction medium can occupy up to 60% or as little as of the reactor volume. Generally, however, in batch operation the reaction medium occupies between 30 and 50% of the reactor volume.

The time of reaction depends upon such interdependent variables as temperature, pressure, and amount and type of catalyst employed. Under preferred conditions for batch operation the reaction reaches essential completion in from 5 to 20 hours.

The catalysts used in the practice of this invention are those obtained by reducing a phosphomolybdic acid salt of one of the metals of groups I-A, I-B, II-B, III-B Vll-A and the base metals of group VllI of the periodic table with hydrogen at atmospheric pressure and a space velocity of at least 500 reciprocal hours at a temperature in excess of 375 C. and below 500 C., ordinarily for at least six hours, as described and claimed in Arnold and Howk, U. S. patent application, Serial No. 368,489, new U. S. Patent 2,788,258, issued April 9, 1957, filed concurrently herewith.

The phosphomolybdie acid salts of the metals of the aforementioned groups used in preparing the reduced metal phosphomolybdate catalysts employed in the practice of this invention correspond to the formula in which y is an integer from 1 through 10, preferably 2 through 10, and M is a metal from groups I-A, IB, Il-B, ill-B, VII-A and the base metals of group VIII of the periodic table, such as copper, silver gold, zinc, aluminum, mercury manganese, masurium, iron, nickel, cobalt, potassium and sodium.

The preferred reduced metal phosphomolybdates are comprehended by the formula M P2MO2 25037 5, wherein M is a metal of groups I-A, I-B, II-B, III-B, VII-A and the base metals of group VIII of the periodic table, y is an integer of from 1 through 10, preferably 2 through 10. The metals of these specified groups are listed in Table VllL-The periodic series of the elemerits on page 118 of Mellors Modern Inorganic Chemistry, revised and edited by Parkes, Longmans, Green and Co., New York, 1952, as follows: Group I-A, lithium, sodium, potassium, rubidium and caesium; Group L-B, copper, silver and gold; Group II-B, zinc, cadmium and mercury; Group III-B, aluminum, gallium and indiam; Group VIIA, manganese and masurium; and the base metals of Group VIII, iron, cobalt and nickel.

Typical reduced metal phosphomolybdates are those where M is nickel, cobalt, iron, manganese, zinc, aluminum, copper, silver and potassium.

The composition of the reduced phosphomolybdic acid metal salt depends upon the temperature and time of reduction used within the preferred operating temperature of 400-475 C. and a 16-25 hour reduction time. In the reduction, hydrogen alone, or hydrogen and diluent gas, e. g., nitrogen or carbon monoxide, is permitted to pass at atmospheric pressure over the heated phosphomelybdic acid. Usually the space velocity is between 500 and 1100 reciprocal hours because under these conditions good reduction rates, under the preferred temperature conditions, are realized.

The amount of catalyst used depends upon such interdependent variables as temperature, pressure, general method of operation, catalyst activity, etc. As a rule in batch operation it will be between 1.5 and 30% and preferably between 2.5 and 20% by weight of the reaction medium employed. In continuous operation, the weight of product in the reactor at any one time is ordinarily less than the weight of the catalyst, but the total weight of material processed during the active life of the catalyst is usually considerably more than the catalyst weight.

The surface of the reactor in contact with the reactants appears to be a factor in determining the molecular weight and yield of high molecular weight hydrocarbons obtained. Silver and stainless steel are satisfactory materials.

The process of this invention makes it possible to convert carbon monoxide to normally solid, high molecular weight hydrocarbons, having properties which make them outstandingly useful for conversion to films and fibers.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

We claim:

1. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 125 to 350 C. under a pressure of at least 200 atmospheres and in contact with a metal phosphomolybdate represented by the formula wherein M is a metal selected from the class consisting of lithium, sodium, potassium, rubidium, caesium, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, manganese, masurium, iron, cobalt and nickel, and y is an integer from 2 through 10.

2. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 150 to 275 C. under a pressure within the range of 400 to 5000 atmospheres and in contact with a metal phosphomolybdate represented by the formula M P Mo O wherein M is a metal selected from the class consisting of lithium, sodium, potassium, rubidium, caesium, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, manganese, masurium, iron, cobalt and nickel, and y is an integer from 2 through 10.

3. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 150 to 275 C. under a pressure within the range of 400 to 5000 atmospheres and in contact with a metal phosphomolybdate represented by the formula h f P Mo O wherein M is a base metal of group VIII of the periodic table and y is an integer from 2 through 10.

4. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 150 to 275 C. under a pressure within the range of 400 to 5000 atmospheres and in contact with a metal phosphomolybdate represented by the formula M P l/lo O wherein M is a metal of group I of the periodic table and y is an integer from 2 through 10.

5. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of to 350 C. under a pressure of at least 200 atmospheres and in contact with a nickel phosphomolybdate represented by the formula Ni P 0 2 5) 11 6. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at a temperature of 125 to 350 C. under a pressure of at least 200 atmospheres and in contact with a cobalt phosphomolybdate represented by the formula C0 P 0 2 5) n 7. A process for preparing normally solid, high molecular weight, hydrocarbon polymers which comprises heating and reacting carbon monoxide with hydrogen at IeastQOQ atmospheres: andeinicontact with au iron;:pho s+ phomolybdaterrepresented bythQsfOFBlLllErE.

8.- A process for preparingp normal-1y solid, high 1110- Iecular; weight, hydrocarbon, polymers which comprises; heating and. reacting carbon-monoxidei at a temperature. of: 125 t 350? C. .under. a; pressure oftat 1east1200 atmospheres: andiin. contactwith iawcopper phosphomolybda-te; represented by the formula 9. A process for preparing normally solid, high: mo lecular. weight, hydrocarborr polymers which comprises heating and reacting,carborrmonoxidet-with hydrogen at a temperature-of 125v to-35.0? C. under apressure; of. at least 1200'. atmospheres. land incontact :with a zinc phosphomolybdate representedby, the-formula se (M 2 5) is 10. A process for preparing normally solid, high molecular: weight, hydrocarbon polymers which comprises heating and. reactingcarbon monoxide withhydrogenat a temperature of 12510350 Cl under: a pressure: of at least,I200I'atmospheres andain contact with a metal phosphomolybdate represented by the formulav wh'erein M'isnickel 'andy i'saninteger from 2 through 10;

1 1.. A process for preparing normall'y solid, high molecular weight, hydrocarbon polymers which compriseswith; r hydrogen.

12; Ar,- prtocess; forrpreparing normally-. soli'd, .highamu leculari weight, ,hydrocar bon 1 polymers. which comprises: heatingand reactingicarbon monoxide .witbvhydrogenzat a temperature or? Z to 350 undersa; pressure-:ofat:

least 200 atmospheres and in contact with a metal phosphomolybdate: representedsby thee:formnla= ikPz'M z'n-as a'z-sa wherein M is ironand y;is,ar1integerfrom 2, through 10.

13. A process for preparing normally; s o1id,. -higl1 mo-- lecularweight; hydrocarbon polymers which comprises heating and reactingecarbon monoxide. with hydrogenat a temperature of 12 5,-.to 35.03 C. under a pressure ofiat; least 20Qvatmospheres andiim contact with .a-metal phos phomolybdate represented. by, the formula whereiniMfisJcopper and y. i'slan integer from 2' through.

wherein M is zinc and y is an integer from 2 through 10.

References: Gifted in-the file ofthis-patent UNITED STATES: PATENTS I 2,632,014 Gresham Mar. 17', 1953' 2,652,372 Farlow Sepia 15, 1953" 2,7145583 Fawcett- Aug; 2;; 1955 8 wherein-:M-iistcobalt'arrdayis. amint'egemfromr-zl-througk;

U S DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE or CORRECTION Patent No. 2,825,705 Herrick R. Arnold et al. v March 4, 1958 It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Let cers Patent should read as corrected below.

Column 3, line 6, for "Ni P O (Mo O read --Ni 'P O -(Mo O column 4, line 18, in the table, first column thereof, second item, for '3Fe0--P O 22lvioO :56H O" read -=-3FeO-P O -22MoO -56H O--; Column 5, line 34,

2 5 after "silver" insert a Comma.

Signed and sealed this 17th day of June 1958.

(SEAL) Attest:

KARL H.a AXL INE ROBERT C. WATSON Attesting Officer Commissioner of Patents 

1. A PROCESS FOR PREPARING NORMALLY SOLID, HIGH MOLECULAR WEIGHT, HYDROCARBON POLYMERS WHICH COMPRISES HEATING AND REACTING CARBON MONOXIDE WITH HYDROGEN AT A TEMPERATUER OF 125* TO 350*C. UNDER A PRESSURE OF AT LEAST 200 ATMOSPHERES AND IN CONTACT WITH A METAL PHOSPHOMOLYBDATE REPRESENTED BY THE FORMULA 